An oil level gauge, or dipstick, is used to determine the level of the oil in the oil pan of an automobile. The oil level is determined by withdrawing the dipstick and noting how high the oil has risen on the dipstick. The gauge is inserted and held in an oil filler tube equipped with a flexible clamping member. This clamping member is made to engage a cover on the gauge to prevent the gauge from coming out of the filler tube. When the oil level is to be measured, the gauge is withdrawn from 15 the filler tube. To accomplish this, the clamping member is disingaged from the cover of the gauge with the tip of a finger or the like. The finger then engages the hook at the top of the gauge, and the gauge is withdrawn.
In the case of an oil level gauge adapted for use with an automotive automatic transmission, the engine and the accessory parts are closely spaced. Therefore, it is difficult to insert a finger between the engine and the accessory parts. To permit the above-described manipulations, it is necessary to maintain the position of the clamping member high. Thus, it is necessary that a long filler tube extend upward from the oil pan located at the lowermost position in the transmission and that the tube must be bent in three dimensions to prevent it from interfering with the automotive body or other device. An oil level gauge inserted into the filler tube must have a length equal to the length of the vertical portion of the filler tube. Furthermore, the gauge must be made of a flexible spring steel and be twisted in a complicated manner to bend in conformity to the bend of the filler tube.
Various gauges have been made, taking into account the foregoing problems and the difficulty of machining the filler tube, to adapt the oil level gauge to automobiles with automatic transmissions and to various engine designs. As an example, a known oil level gauge is used with a filler tube divided into a lower tube and an upper tube. To enable the gauge to be installed in any of various automobiles, only the shape of the upper tube is modified.
With the known oil level gauge described just above, the filler tube is bent over a long distance in three dimensions and so the gauge inserted into the tube is also long. In addition, the gauge must be flexible enough to adapt itself to the three-dimensional bend of the tube. In this way, the gauge is wasteful in configuration. Similarly, the filler tube must be made much longer than needed to provide the necessary function. Further, it is not always easy to withdraw the gauge.
Meanwhile, it is important that the cover of the gauge be positively clamped against the open end of the filler tube. If the clamp is not secured, then foreign matter such as rainwater or dust may enter from the gap around the gauge cover and mix with the oil. As a result, a valve in the automatic transmission may stick. Consequently, the clamping position cannot be altered without a reliable clamping means. For these reasons, reductions in the lengths of the gauge and the filler tube have not been accomplished. Also, it has been impossible to straighten them, for the reasons stated.